For the first time since the mid-80s, the Environmental Protection Agency has revised the test used to measure city and highway fuel consumption.

The goal is to provide a more accurate estimate of what you'll get in real-life driving.

That means new cars and trucks are being tested at higher speeds, with harder acceleration and the air conditioning on for part of the time.

As a result,'08 mileage estimates are down 10% to 25% from comparable '07 models.

The largest declines are for cars with four-cylinder engines and hybrid powertrains, which must worker harder than larger engines when the AC is on or you really punch the accelerator.

The new test reduced the city mileage for a typical compact by 4 m.p.g., and by 10 m.p.g. for some hybrids. Models with V6 and V8 engines only lost 1 or 2 m.p.g.